The writer posted on Yelp that Chunyee Lu, owner of the Guadagnini Violin shop at 407 S. Dearborn St., was a “ripoff artist.”

The lawsuit filed Tuesday in Cook County Circuit Court identifies the defendant only by the online monikers used on various review sites: TRUTHETELLER1790, TRUTH TELLER and TRUTH T. But the common IP address suggests they’re all the same person, Lu’s attorney, James Branit, alleges.

The comments were posted last January on Yelp, as well as CitySearch.com, Kudzu.com, and MerchantCircle.com.

The writer, under the name “TruthT.,” posted on Yelp: “Would you like to buy a gold mounted tortoise shell bow for $4500 that is actually worth $800 and is, in fact, made of gold-colored metal and faux-plastic shell? Then please go to this shop!”

Under another moniker, “Truthteller1790” posted a comment titled “RIPOFF ARTIST.” In the post, the critic states: “Please don’t go to this shop unless you want to be sold something which isn’t what its (SIC) purported to be for an outrageous price. They also will try to convince you your instrument needs a super expensive repair when it (SIC) just need an adjustment. Ripoff.”

Branit says the comments are false and misleading and the writer should be held accountable.

“One concern is that something like this can be done by a competitor of ours or, by somebody who is seeking to harm us for whatever personal reason they have,” Branit told the Chicago Sun-Times, adding: “Society has to balance the injury that’s being done by these anonymous reviews with the interest society has in allowing people to write these sorts of things anonymously.”

Lu has filed a separate legal action to unmask the writer’s identity. Last year, they went to court and asked RCN — which sells bundled cable, phone and internet service — to track the identity of the owner through the IP address, Branit said. That case is still pending.

Guadagnini’s has been in business for 25 years. In the suit, Lu boasts of decades of experience in restoring fine instruments and bows, and counts some of the most influential musicians around the world as clients.

The suit is seeking in excess of $50,000 in damages.

The Chicago Sun-Times contributed to this report, via the Sun-Times Media Wire.